Residue Depletion of Imidocarb in Bovine Tissues by UPLC-MS/MS

SIMPLE SUMMARY: Bovine protozoal disease is a common disease that causes huge economic losses to the cattle breeding industry. Imidocarb (IMD) can be used to treat protozoal parasite diseases in cattle including babesiosis, anaplasmosis, and eperythrozoonosis. However, residues of imidocarb in bovine tissues pose a risk to food safety. This study conducted a residue depletion of imidocarb in cattle based on an ultra-high performance liquid chromatography-tandem mass spectrometry method and obtained the IMD withdrawal time in cattle by the calculation through the WT1.4 software. The results show that the liver and kidney may be the target tissues for IMD and the withdrawal time of IMD in cattle is 224 days at the dosage of 3.0 mg/kg. This will guide farmers in the proper use of imidocarb and ensure human food safety. ABSTRACT: In this study, an ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the residue depletion of imidocarb (IMD) in bovine tissues, and the drug withdrawal time of IMD was determined. Twenty-five clinically healthy cattle (body weight 300 kg ± 15 kg) were randomly divided into five groups of five cattle each. The cattle were treated subcutaneously injecting a single dose of a generic IMD formulation, at the recommended dosage of 3.0 mg/kg. The five groups of cattle were slaughtered respectively at 96, 160, 198, 213, and 228 days after IMD administration. Samples from the liver, kidney, muscle, fat, and injection site were collected from each animal. After subtilis proteinase was used to digest the tissue, the content of IMD in the samples was analyzed by UPLC-MS/MS method. In conclusion, the method validation results showed that the method meets the criteria, and the longest withdrawal time of 224 days for the liver can be selected as the conclusive withdrawal time to guarantee consumer safety.